I know of no such thing as the 'Cretaceous-theory'!
However you probably mean the The Cretaceous-Tertiary extinction event, which occurred approximately 65.5 million years ago.
If this is the case then, the theory regarding this is that, a comet or asteroid (an impactor) hit the Earth at this point and caused the extinction event.
Impactors frequently contain levels of the element iridium not found in normal Earth rocks, and a worldwide distributed spike in the iridium content of a specific geological layer would seem to support the fact that an impactor had a global affect.
However please note, that while much is made of the impactor theory for the extinction of the dinosaurs, the most recent geological research seems to prove definitively that dinosaurs were present on the planet for some hundreds of thousands of years after the iridium spike and thus, while the impactor certainly happened, it is not directly responsible for the demise of the dinosaurs.
See the related link below.
Some asteroids do have high levels of iridium, but it is not a universal trait. Iridium is found in varying concentrations in different types of asteroids, depending on their composition and origin. The presence of iridium in an asteroid can provide insights into its history and formation.
The element that has been linked to the extinction of the dinosaurs is iridium. High levels of iridium have been found in sediment layers around the world from the time of the dinosaur extinction, suggesting that it may have come from an asteroid impact.
Either. However the natural form is rare on the surface of the earth, but higher levels are in some igneous rocks, some lavas, and all meteorites.
Triglyceride levels are very important because they deal with your heart health. If your levels are too high then you will be dealing with some serious health issues that could eventually turn life threatening.
During the past 500,000 years, levels of carbon dioxide in the atmosphere never rose above 300 ppm (parts per million) or 0.03%. Since the Industrial Revolution, 200 years ago, when we began burning coal, levels have risen to their present (2013) levels of 400 ppm (parts per million) or 0.04%.
Some asteroids do have high levels of iridium, but it is not a universal trait. Iridium is found in varying concentrations in different types of asteroids, depending on their composition and origin. The presence of iridium in an asteroid can provide insights into its history and formation.
The element that has been linked to the extinction of the dinosaurs is iridium. High levels of iridium have been found in sediment layers around the world from the time of the dinosaur extinction, suggesting that it may have come from an asteroid impact.
Elevated arterial ammonia levels are almost always present in hepatic coma, but levels are not necessarily correlated with the severity or extent of the disease.
levels of variables important in statistical analysis?
C-O levels typically refer to carbon monoxide levels in the air. Carbon monoxide is a toxic gas that can be harmful to human health when present at high levels. Monitoring C-O levels is important for ensuring indoor air quality and preventing exposure to this dangerous gas.
The ozone levels are very low now. They were ok before the invention of CFC's.
The original observation was that in the fossil records there is a layer with high levels of iridium and osmium at the time of dinosaur extinction. Iridium and osmium are common is asteroids. For the layer to be all over the globe it must have been a major strike which would have caused global wide climate change causing a mass extinction.
It is important to monitor the ozone levels. It is to keep check on the depletion.
Potassium levels in the body are typically measured through a blood test. The test measures the amount of potassium present in the blood, which helps determine if levels are within a normal range. Potassium levels are important for maintaining proper muscle function, nerve activity, and fluid balance in the body.
In fact, the studies indicated CRP levels may be as important--if not more important--in predicting and preventing heart disease as cholesterol levels are.
Meiosis
High levels of lime in well water can cause stomach discomfort and digestive issues in some individuals. It is important to have your well water tested to determine the specific levels of lime and other minerals present to ensure safe consumption.